Snow Tyres

admin December 3rd, 2005

This is the first of a series of bulletins to be issued by snowtyres.com.au to communicate issues and safety information to vehicle operators involved in the snow and alpine areas of Australia. The new information bulletins will be mailed on a regular basis to users of snow tyres and to our industry friends and colleagues.

We welcome your feedback and we would be pleased to receive any information or testimonials on your experience with snow tyres that we could share with others receiving the bulletins.

CONTENTS

• Background
• Nokian product range
• Why Nokian snow tyres work so well
• Snow tyre F.A.Q’s
• The snowflake-on-the-mountain-peak symbol and M+S markings
• Performance comparisons with different types of 4WD tyres
• Snow tyre testing

Background

Since 1985 the Camberwell store of Roof Carrier Systems Pty Ltd has become well known as a supplier of quality roof carrier systems and RUD snow chains. During the 2004 ski season Roof Carrier Systems expanded the business to include Nokian snow tyres from Finland. Because safety is a paramount consideration for many operators Nokian snow tyres are now being used on vehicles based at Mt Buller, Falls Creek, Mt Hotham, Mansfield and Bright in Victoria and at Thredbo, Perisher and Jindabyne in NSW.

There are images of many of these vehicles on our website in the Gallery section.

For further information of how you can improve the safety and the effective operations of your fleet vehicles with Nokian snow tyres please contact Richard Townley at Roof Carrier Systems Pty Ltd on 03 9822 9539 or 0418 324 052. We can discuss your requirements for snow tyres for the 2006 snow season and provide you with details of pricing and availability.

Nokian product range

The Nokian range includes snow tyres for cars, 4WDs, AWDs as well as buses, vans and light trucks. There are five different tread patterns, all with different load and different speed ratings.

• Nokian WR the severe service winter tyre for cars & compact AWDs that can be used all year
• Nokian RSi severe service winter tyre for cars and compact AWDs
• Nokian WR SUV the severe service winter AWD tyre that can be used all year
• Nokian Hakka SUV severe service winter tyre for 4WDs
• Nokian Hakka LT severe service winter tyre for light trucks and buses
• Nokian Hakka CS severe service winter tyre for light commercial vehicles and mini buses

All Nokian snow tyre specifications are on our Product section of the website.

Why Nokian snow tyres work so well

Thanks to their special compound Nokian winter tyres offer the elasticity to ensure maximum grip throughout the snow season, regardless of the road conditions. Summer tyres become like hard plastic when the temperature falls below 7° thereby losing the flexibility needed to build up sufficient grip for braking, for starting traction and for cornering. Because of their greater suppleness in the cold, Nokian tyres are able to interlock with asphalt, snow and ice, even at low temperatures.

Off-road and all-terrain 4WD tyres are not specifically designed for snow driving either.
These types of tyres are designed for off-road driving on gravel, sand and rocks and can also have a very high noise level. Because off-road tyres have very limited siping on their tread they provide little traction in icy conditions.

Nokian snow tyres features include special silica compounds, arrowhead tread pattern and dense tread siping to give a higher level of safety.

Reports from the drivers and operators of the vehicles using Nokian snow tyres that are in service in these areas have been excellent in relation to improved safety, increased traction, shorter stopping distance, reduced wheel lock-up, long tread life and low road noise.

Always remember that no matter how many safety features your vehicle has it is the tyres that determines how it drives and handles on snow and ice.

Look for the snow-flake-on-the-mountain-peak symbol

Even with the M+S marking some tyres can not be recommended without reservations for driving on snow and ice. This is especially true for all-season tyres and all-terrain tyres. AWD vehicles should be fitted with correct severe service winter tyres that can be recognised by the snow flake-on-the-mountain-peak symbol on the side of the tyre.

From Auto Motor und Sport - Issue 25/2004

Snow tyre F.A.Q’s

Do vehicles really need snow tyres?
We all know that tyres are a compromise. One tyre can’t be the fastest on the track, most controllable in the snow, the safest on ice, the longest wearing or the best off-road. The high performance tyres, now being fitted to many new AWDs, that grips the highway at high tread temperatures is unsafe as its tread compound becomes like “hard plastic” at below 7°.

Today’s tyre tread designs and compounds maximize long, even wear… not winter traction. While many of today’s Original Equipment tyres address some of these issues, they still emphasize longer wear, a quieter ride or greater performance…not winter traction. Only severe service snow tyres are designed to excel in the colder temperatures, slush, snow and ice that alpine areas experience for three or more months a year.

What If the vehicle has traction control?
Traction control will help keep you from overpowering your tyres, it doesn’t actually improve your tyre’s traction. Traction control simply limits the vehicles take off and acceleration to the traction level of its tyres. The only way to maximize any vehicle’s winter performance is to provide the traction control with more grip to work with by using tyres specifically designed for winter snow and ice driving conditions.

What If the vehicle has ABS brakes?
To give you an idea of stopping distances look at the difference in braking distance of a 4WD with ABS in the table Performance comparisons with different types of 4WD tyres. ABS brakes will help keep you from locking up your tyres, it doesn’t actually improve your tyre’s traction. ABS simply limits your vehicles braking to the traction level of your tyres. The only way to reduce the stopping distance and to maximize the vehicle’s winter performance and safety is to provide the ABS brakes with more grip to work with by using tyres specifically designed for winter snow and ice driving conditions.

What If the vehicle has All-Wheel Drive?
4WD and All-Wheel Drive is certainly an advantage…but its advantage can be multiplied by using severe service winter tyres designed for the road conditions you’ll encounter. While more tyres share the torque of your vehicle, think of the ice and snow performance that severe service snow tyres provide. All of the reasons that encouraged you to select an all-wheel drive are the same reasons that dedicated snow tyres will make your winter driving safer and enhance your vehicles braking, handling and cornering capacity.

However, it is important to remember that while the all-wheel drive vehicle’s ability to accelerate in slippery conditions provides a lot of confidence, it doesn’t really offer any unique advantage when the vehicle has to stop or turn. This is because the other vehicles also use all four tyres to provide braking and cornering traction.

Since all-wheel drive vehicles actually weigh more than their two-wheel drive counterparts, bringing them to a stop or turning a corner actually requires more traction. So, whether your vehicle has anti-lock brakes, traction control, a vehicle stability system or all-wheel drive, it is your tyres that provide the real traction. Obviously, the more tyre traction these systems have to work with the better. Since most all-wheel drive vehicles are equipped with all season tyres, with high summer performance tyres or are fitted with off-road and all-terrain tyres, optimizing the vehicles systems capabilities for winter snow and ice driving conditions requires installing severe service snow tyres.

The traction, braking and cornering difference of 4WD tyres is shown in the Performance comparisons with different types of 4WD tyres section of this bulletin.

The snowflake-on-the-mountain-peak symbol and M+S markings

You will find the M+S symbol on most all-season tyres and even on off-road and all-terrain tyres. Summer tyres will not have this designation. For a tyre to get the M+S designation it must only have a specified tread-to-void ratio. It does not mean that a tyre with the M+S symbol has passed any actual tests for its effectiveness in severe winter conditions.

The snowflake-on-the-mountain-peak symbol indicates a severe snow service conditions rating. Tyres bearing this symbol will provide snow performance far superior to tyres only bearing the M+S symbol

All Nokian snow tyres have the snowflake-on-the-mountain-peak severe service emblem denoting that they have been tested and approved as a traction tyre suitable for use in severe snow conditions. These are the safest tyres for any kind of winter driving. Some US ski resorts will not even let you up the mountain if you do not have this symbol on your tyres.

What’s the difference between the snow traction of a M+S (mud and snow) branded tyre, a traditional all-season tyre, and a dedicated winter tyre? While many consumers probably aren’t sure, it can be the difference between getting home… or going off the road.

The traditional M+S definition for tyres is a geometric based formula on a specified tread-to-void ratio. The tyres meeting this formula are branded on at least one sidewall with the letters “M” and “S”, (e.g., M&S, M+S, M/S, MS, etc.), which were first used to differentiate the knobbly bias ply tyres intended for use on muddy, and/or snow covered roads from the straight rib tyres used on early cars or trucks. Then when radial ply tyres were also found to deliver more snow traction than the straight rib bias ply tyres, the tyre company marketing departments saw an opportunity, and the term “all-season tyre” was born. Supported by advertising, all-season tyres have presented an unspoken promise that they, throughout their life, can provide traction for all-seasons…through spring’s rain, summer’s heat, autumn’s cooling and winter’s snow. And while this combined offering made all-season tyres popular, the problem is that this geometric definition doesn’t guarantee performance or any degree of safety in winter driving.

In 1999, The U.S. Rubber Manufacturers Association (RMA) and the Rubber Association of Canada (RAC) agreed on a performance based standard to identify passenger and light truck tyres that attain a traction index equal to, or greater than110 (compared to a reference tyre which is rated 100) during the specified American Society for Testing and Materials traction tests on packed snow. The new standard helps ensure that drivers can easily identify tyres that provide a higher level of snow traction in harsh winter conditions.

Only tyres with the snowflake-on-the-mountain-peak symbol branded on the tyre’s sidewall identifies tyres that have met the required performance in snow testing.

Performance comparisons with different types of 4WD tyres

This table shows the results of a tyre test comparison on a 4WD using five different 265/70 R16 tyres from the same tyre manufacturer. The tyres tested are winter tyres, mud-terrain tyres, all-season tyres, all-terrain tyres and summer tyres.

The original fitment tyres of many 4WD vehicles that are based at the alpine resorts in Australia have been replaced with all-terrain or mud-terrain tyres because of the poor winter performance limits of the OE all-season and summer tyres. These off-road tyres are not designed by the tyre manufacturer as a severe service tyre for driving in snow and icy conditions either.

You can see from these tests the significant advantage and increased safety that is provided with the use of correct winter tyres over all the other tyre types.

Traction – snow (% difference to the tested winter tyre)
SJ6 - Winter tyre (5170 newtons)
MT2 - Mud-terrain tyre (3116 newtons) -39.7 %
ST1 - All-season tyre (3115 newtons) -39.7 %
AT2 - All-terrain tyre (3064 newtons) -40.7 %
PT1 - Summer tyre (2707 newtons) -47.6 %

Braking from 50 km/h - snow
SJ6 - Winter tyre (32.8 metres)
MT2 - Mud-terrain tyre (44.0 metres) +34.2 %
ST1 - All-season tyre (47.5 metres) +44.8 %
AT2 - All-terrain tyre (48.1 metres) +46.6 %
PT1 - Summer tyre (50.0 metres) +52.4 %

Handling - snow
SJ6 - Winter tyre (53.4 km/h)
MT2 - Mud-terrain tyre (47.7 km/h) -10.7 %
ST1 - All-season tyre (45.1 km/h) -15.5 %
AT2 - All-terrain tyre (42.4 km/h) -20.5 %
PT1 - Summer tyre (42.0 km/h) -21.3 %

The tables show test comparisons on a Mitsubishi Pajero using five different 265/70 R16 tyre types that are available Dunlop for 4WDs. These standardised tests are conducted using a calibrated winch system to measure take off torque (traction), a braking test from 50km/h and a handling or cornering test based on a 25 metre radius test track.

Reprinted from the German 4WD magazine AutoBild Alles Allrad 8/2004

Snow tyre testing.

Safety is a paramount consideration for all the alpine resort management boards. They all apply risk management principles and seek to maintain a safe work place and environment for all their employees and visitors. One of the increasing areas of concern is the potential of conflict between skiers, pedestrians and vehicles especially because of the shared use of village roads access roads and car park areas. This problem is increasing because of the large number of AWD vehicles that are fitted with high performance “ summer “ tyres with V - 240km/h, W – 270 km/h or Y – 300 km/h speed rating.

The use of 4WD vehicles in ice and snow areas when fitted with these high performance tyres can be said to be unsafe as these tyres provide unacceptable traction and braking. This is because these tyres, when they are fitted to these vehicles, were not designed by the tyre manufacturer to be driven in winter snow and ice driving conditions.

Currently 4WD vehicles in NSW are currently not required to carry snow chains and in Victoria 4WD vehicles are “generally exempted from fitting snow chains” even though they are required to carry them.

NSW - The Traffic Operations Division of the NSW Roads and Traffic Authority (RTA) is very progressive and has been actively trialing the use of Nokian severe service winter tyres as an alternative to snow chains on five of their vehicles during the 2005 winter. Additional snow tyre testing on high performance AWD vehicles was conducted at Perisher, in conjunction with the RTA, in July and September 2005 and this testing will be completed during the winter of 2006. The RTA has been conducting a comprehensive vehicle incident survey and will recommend that all 4WDs carry snow chains from 2006 and are likely to enforce this requirement from 2007.

VICTORIA – Areas of the Victorian Alpine region are declared as hazardous areas each winter by VicRoads. During this period all vehicles must carry correctly fitting snow chains and there are special accreditation conditions for buses and for bus drivers when operating in these hazardous areas. Even though VicRoads state that “icy roads are of particular concern”, 4WD vehicles are “not required to have chains fitted when travelling in snowy areas in Victoria” as 4WDs are “generally exempted from fitting snow chains.”

At this time VicRoads have not evaluated the safety or performance of any 4WD vehicles fitted with high performance “ summer “ tyres, in snow and ice conditions with or without wheel chains being fitted. The table Performance comparisons with different types of 4WD tyres really highlights the safety issues of correct tyre selection, particularly the braking performance.

Based on this information we should question the safety for all road users in exempting 4WD vehicles using high speed rated “summer” tyres from fitting wheel chains in snow and ice conditions.

Additional snow tyre comparison testing will be included in future issues of The Snow Tyre Bulletin.

The performance and safety of Nokian snow tyres has been evaluated on many vehicles based at Buller, Hotham, Perisher and Thredbo during the 2005 snow season. Images of these vehicles are on our Gallery Page.

There is a test procedure for measuring snow performance of tyres that has been prepared by The German Testing Authority, TUV Automotive GMBH,

Annex VIII of “SURVEY ON MOTOR VEHICLE TYRES & RELATED ASPECTS (ENTR/02/045)” details the “Test procedure for measuring snow performance of tyres”.

Copies are available on request.

There are two DVDs are also available on request from snowtyres.com.au

• Nokian Snow Tyres – Where safety begins, and
• Modern Winter Driving Techniques - Winter Driving School at Steamboat

TOPICS IN NEXT ISSUES OF THE SNOW TYRE BULLETIN

- 4WD winter tyre performance reduces with tread wear
- Traction comparisons - winter & summer tyres
- Traction comparisons - tyres with & without snow chains
- Winter tyres tested using 2WD BMW 5 Series sedan
- Winter tyre test conducted in New Zealand using VW Touareg V8 AWD
- Snow chain tests - 12 chains tested in Sweden
- Nokian snow tyre users in Australia

For further information of how you can improve the safety and the effective operations of your fleet vehicles with Nokian snow tyres and with Rud snow chains please contact Richard Townley at Roof Carrier Systems Pty Ltd by Phone 03 9822 9539 or Mobile 0418 324 052.

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